We claim the ornamental design for a rectangular shaped flow through cap, as shown and described.
FIG. 1 is a side perspective view showing the rectangular shaped flow through cap;
FIG. 2 is a side view thereof;
FIG. 3 is a top view thereof; and,
FIG. 4 is a bottom view thereof.
The surface shading is for purposes of illustrating the contour and appearance of the claimed surfaces upon which it is illustrated. The broken lines are used to show unclaimed portions of the invention and form no part of the claimed design.